diff --git a/layout/inspector/InspectorUtils.cpp b/layout/inspector/InspectorUtils.cpp
index b0ea469d91dc..5acd5dbf67ac 100644
--- a/layout/inspector/InspectorUtils.cpp
+++ b/layout/inspector/InspectorUtils.cpp
@@ -24,7 +24,6 @@
 #include "nsRuleNode.h"
 #include "nsIStyleRule.h"
 #include "mozilla/css/StyleRule.h"
-#include "nsICSSStyleRuleDOMWrapper.h"
 #include "nsIDOMWindow.h"
 #include "nsXBLBinding.h"
 #include "nsXBLPrototypeBinding.h"
diff --git a/layout/style/ServoStyleRule.cpp b/layout/style/ServoStyleRule.cpp
index 29b1607227e2..6bb3390bf9cf 100644
--- a/layout/style/ServoStyleRule.cpp
+++ b/layout/style/ServoStyleRule.cpp
@@ -125,13 +125,7 @@ ServoStyleRule::ServoStyleRule(already_AddRefed<RawServoStyleRule> aRawRule,
 {
 }
 
-// QueryInterface implementation for ServoStyleRule
-NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(ServoStyleRule)
-  NS_INTERFACE_MAP_ENTRY(nsICSSStyleRuleDOMWrapper)
-NS_INTERFACE_MAP_END_INHERITING(css::Rule)
-
-NS_IMPL_ADDREF_INHERITED(ServoStyleRule, css::Rule)
-NS_IMPL_RELEASE_INHERITED(ServoStyleRule, css::Rule)
+NS_IMPL_ISUPPORTS_CYCLE_COLLECTION_INHERITED_0(ServoStyleRule, css::Rule)
 
 NS_IMPL_CYCLE_COLLECTION_CLASS(ServoStyleRule)
 
@@ -203,15 +197,6 @@ ServoStyleRule::List(FILE* out, int32_t aIndent) const
 }
 #endif
 
-/* nsICSSStyleRuleDOMWrapper implementation */
-
-NS_IMETHODIMP
-ServoStyleRule::GetCSSStyleRule(BindingStyleRule **aResult)
-{
-  NS_ADDREF(*aResult = this);
-  return NS_OK;
-}
-
 /* CSSRule implementation */
 
 uint16_t
diff --git a/layout/style/ServoStyleRule.h b/layout/style/ServoStyleRule.h
index 4e50df49028e..7046334d0ce4 100644
--- a/layout/style/ServoStyleRule.h
+++ b/layout/style/ServoStyleRule.h
@@ -13,8 +13,6 @@
 #include "mozilla/ServoBindingTypes.h"
 #include "mozilla/WeakPtr.h"
 
-#include "nsICSSStyleRuleDOMWrapper.h"
-#include "nsICSSStyleRuleDOMWrapper.h"
 #include "nsDOMCSSDeclaration.h"
 
 namespace mozilla {
@@ -59,7 +57,6 @@ private:
 };
 
 class ServoStyleRule final : public BindingStyleRule
-                           , public nsICSSStyleRuleDOMWrapper
                            , public SupportsWeakPtr<ServoStyleRule>
 {
 public:
@@ -73,9 +70,6 @@ public:
 
   MOZ_DECLARE_WEAKREFERENCE_TYPENAME(ServoStyleRule)
 
-  // nsICSSStyleRuleDOMWrapper
-  NS_IMETHOD GetCSSStyleRule(BindingStyleRule **aResult) override;
-
   uint32_t GetSelectorCount() override;
   nsresult GetSelectorText(uint32_t aSelectorIndex,
                            nsAString& aText) override;
diff --git a/layout/style/StyleRule.cpp b/layout/style/StyleRule.cpp
index a13417b56b14..5915458f59f8 100644
--- a/layout/style/StyleRule.cpp
+++ b/layout/style/StyleRule.cpp
@@ -1194,14 +1194,6 @@ StyleRule::Style()
   return mDOMDeclaration.get();
 }
 
-NS_IMETHODIMP
-StyleRule::GetCSSStyleRule(BindingStyleRule **aResult)
-{
-  *aResult = this;
-  NS_ADDREF(*aResult);
-  return NS_OK;
-}
-
 StyleRule::StyleRule(nsCSSSelectorList* aSelector,
                      Declaration* aDeclaration,
                      uint32_t aLineNumber,
@@ -1247,7 +1239,6 @@ NS_INTERFACE_MAP_BEGIN_CYCLE_COLLECTION(StyleRule)
     return NS_OK;
   }
   else
-  NS_INTERFACE_MAP_ENTRY(nsICSSStyleRuleDOMWrapper)
 NS_INTERFACE_MAP_END_INHERITING(Rule)
 
 NS_IMPL_ADDREF_INHERITED(StyleRule, Rule)
diff --git a/layout/style/StyleRule.h b/layout/style/StyleRule.h
index 0b1086ce5271..fb2e7650a954 100644
--- a/layout/style/StyleRule.h
+++ b/layout/style/StyleRule.h
@@ -22,7 +22,6 @@
 #include "nsCOMPtr.h"
 #include "nsCSSPseudoElements.h"
 #include "nsIStyleRule.h"
-#include "nsICSSStyleRuleDOMWrapper.h"
 
 class nsAtom;
 struct nsCSSSelectorList;
@@ -318,7 +317,6 @@ namespace css {
 class Declaration;
 
 class StyleRule final : public BindingStyleRule
-                      , public nsICSSStyleRuleDOMWrapper
 {
  public:
   StyleRule(nsCSSSelectorList* aSelector,
@@ -334,9 +332,6 @@ public:
   NS_DECL_CYCLE_COLLECTION_SCRIPT_HOLDER_CLASS_INHERITED(StyleRule, Rule)
   bool IsCCLeaf() const override;
 
-  // nsICSSStyleRuleDOMWrapper
-  NS_IMETHOD GetCSSStyleRule(BindingStyleRule **aResult) override;
-
   uint32_t GetSelectorCount() override;
   nsresult GetSelectorText(uint32_t aSelectorIndex,
                                    nsAString& aText) override;
diff --git a/layout/style/moz.build b/layout/style/moz.build
index 923c3b3e1d17..2fa93702653b 100644
--- a/layout/style/moz.build
+++ b/layout/style/moz.build
@@ -55,7 +55,6 @@ EXPORTS += [
     'nsDOMCSSRGBColor.h',
     'nsICSSDeclaration.h',
     'nsICSSLoaderObserver.h',
-    'nsICSSStyleRuleDOMWrapper.h',
     'nsIStyleRule.h',
     'nsIStyleRuleProcessor.h',
     'nsLayoutStylesheetCache.h',
diff --git a/layout/style/nsICSSStyleRuleDOMWrapper.h b/layout/style/nsICSSStyleRuleDOMWrapper.h
deleted file mode 100644
index b063ce927c0a..000000000000
--- a/layout/style/nsICSSStyleRuleDOMWrapper.h
+++ /dev/null
@@ -1,34 +0,0 @@
-/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
-/* vim: set ts=8 sts=2 et sw=2 tw=80: */
-/* This Source Code Form is subject to the terms of the Mozilla Public
- * License, v. 2.0. If a copy of the MPL was not distributed with this
- * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
-
-/*
- * interface to provide DOM inspector with access to internal interfaces
- * via DOM interface
- */
-
-#ifndef nsICSSStyleRuleDOMWrapper_h_
-#define nsICSSStyleRuleDOMWrapper_h_
-
-// IID for the nsICSSStyleRuleDOMWrapper interface
-// {cee1bbb6-0a32-4cf3-8d42-ba3938e9ecaa}
-#define NS_ICSS_STYLE_RULE_DOM_WRAPPER_IID \
-{0xcee1bbb6, 0x0a32, 0x4cf3, {0x8d, 0x42, 0xba, 0x39, 0x38, 0xe9, 0xec, 0xaa}}
-
-namespace mozilla {
-class BindingStyleRule;
-} // namespace mozilla
-
-class nsICSSStyleRuleDOMWrapper : public nsISupports {
-public:
-  NS_DECLARE_STATIC_IID_ACCESSOR(NS_ICSS_STYLE_RULE_DOM_WRAPPER_IID)
-
-  NS_IMETHOD GetCSSStyleRule(mozilla::BindingStyleRule** aResult) = 0;
-};
-
-NS_DEFINE_STATIC_IID_ACCESSOR(nsICSSStyleRuleDOMWrapper,
-                              NS_ICSS_STYLE_RULE_DOM_WRAPPER_IID)
-
-#endif /* !defined(nsICSSStyleRuleDOMWrapper_h_) */